Analog cell phone owners aren't the only ones with something to worry about Monday. Plenty of other devices, such as home security systems and car alarm services, are still using analog transmitters. Home alarm systems may especially be affected, as providers report having customers in areas with little to no GSM reception (though that number is estimated at just under 400,000 as of six months ago).

GM's OnStar service for its cars is in the middle of a rocky transition too, as the company preemptively shut down its analog service on January 1, 2008. Though GM began warning its analog customers last year, upgrading a car with a digital transmitter can cost hundreds of dollars, which customers must pay out of pocket. Upset over the costly change, two OnStar customers in Pennsylvania have filed a lawsuit against GM and are hoping to turn it into a class action.